Egypt’s Army chief called Wednesday for mass rallies to back a crackdown on “terrorism and violence,” in comments quickly slammed as a “threat” by a senior Islamist who vowed to continue protests.

With tensions already running high following the Army’s ouster of President Mohamed Morsi on July 3, the call by Gen Abdel Fattah al-Sisi for protests raises the prospect of further violent showdowns between the pro and anti-Morsi camps.

“Next Friday, all honourable Egyptians must take to the street to give me a mandate and command to end terrorism and violence,” said Sisi, wearing dark sunglasses as he took to the podium to address a graduation ceremony of military cadets near Alexandria.

The general said that before he announced Morsi’s ouster, he had warned the Islamist president he must either resign or hold a referendum.

Huge crowds of Egyptians protested against Morsi on June 30, after just a single turbulent year of his presidency.

Presidential aides “told me if there is any problem there will be lots of violence because of armed groups, to scare me,” Sisi said.

Senior Muslim Brotherhood leader Essam al-Erian in a statement on his Facebook page said Morsi loyalists would not be intimidated by the Army chief’s call for mass rallies.

“Your threat will not prevent millions from continuously protesting,” Erian said, referring to demonstrations by Morsi’s supporters that have continued non-stop since the Islamist leader was pushed aside by Sisi.

Nearly 170 people have died in political unrest in Egypt since the end of June, according to an AFP tally, many of them in clashes between Morsi’s supporters and opponents.

Sisi’s address came just hours after blast in front of a police station in Mansura in the Nile Delta, which Mohamed Sultan, head of the emergency services, told AFP left “28 wounded and one dead.”

The interior ministry said in a statement that a conscript was killed in the blast.

The Islamist anti-coup alliance, which has been pressing demonstrations calling for Morsi’s return, said on Wednesday that it “strenuously condemns the criminal bombing that hit Mansura city.”

It added that it “adheres to peacefulness of protests and denounces all acts of violence that contradict this principle.”

Clashes between supporters and opponents of Morsi, have killed at least 13 people across Egypt since Monday.

Faced with the deadly clashes, interim President Adly Mansour appealed in a speech delivered for a “new page in the book of the history of the nation, without rancour, hatred and confrontation.”

Presidential spokesman Ahmed al-Muslimani also decried the violence.

“Egypt is not a second Syria and anyone who pushes in that direction is a traitor,” Muslimani said.

But Morsi’s detention and subsequent arrests of senior Brotherhood leaders, have hardened his supporters against dealing with the new regime.

His daughter Shaimaa Mohamed Morsi told reporters on Monday that the family would sue Army chief Gen Abdel Fattah al-Sisi and also take legal action outside Egypt.

Senior aides held with the President have asked their families for prison clothes, signalling possible charges, relatives said.

Khaled el-Qazzaz, the former president’s secretary for foreign relations, and top adviser Essam el-Haddad made the request in telephone conversations last Friday, asking for white clothes, their relatives told AFP.

Prisoners awaiting trials or verdicts in Egypt wear white clothes, which may be provided by family members.

In addition to clashes between rival protests on streets across the country, Egypt’s caretaker government is facing a low-level insurgency in the Sinai.

Militants in the restive peninsula have launched almost daily attacks on police and Army checkpoints since July 3, killing 20 security services personnel and 10 civilians.